Due to the trend of being compact and light-weighted for communication devices, such as electronic devices including personal digital assistants (PDAs), mobile phones, and notebook computers, and also due to the increasing need for wireless networking, miniaturization of antenna is now an important challenge for wireless communication products.
The currently available antenna can be classified as dipole antenna, monopole antenna, planar antenna, loop antenna, and disk antenna. Currently, various techniques have been developed for all these kinds of antenna.
For patent documents that are currently known, Taiwan Patent Publication No. M285057 discloses a dual-band monopole antenna, wherein the dual-band monopole antenna comprises a substrate, a first antenna, a second antenna, an impedance path section, and a grounding section.
On a surface of the substrate, two independent antennas, the first and second antennas, which are operated in different frequencies, are formed and the grounding section is provided at the terminals of the first and second antennas at the same side. The grounding section is arranged at a given distance from the terminals of the antennas at the same side and the grounding section is extended to form at least one impedance path section between the first and second antennas.
The impedance path section opposes the first and second antennas and is substantially parallel thereto in a horizontal direction. The impedance path section provides isolation between the radiated signals of the first and second antennas when the first and second antennas are respectively transmitting different signals in limited space on the substrate.